lxc-busybox: add OpenSSH support

Add an additional template parameter for SSH support in the container. Currently
this can be implemented using the Dropbear or OpenSSH utility. The respective
tool needs to be available on the host Linux.

If the parameter is omitted, the template will look for the Dropbear utility on
the host and install it if it is available (legacy behavior).

Adding OpenSSH support has been done following the model in the lxc-sshd
template.

Signed-off-by: Bogdan Purcareata <bogdan.purcareata@freescale.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

diff --git a/templates/lxc-busybox.in b/templates/lxc-busybox.in
index 7e05bd6886eac63b384d6aede691550a5fd15c87..95961a334375b8ccce32e5fffc7234650fcbe3de 100644 (file)
--- a/templates/lxc-busybox.in
+++ b/templates/lxc-busybox.in
@@ -22,6 +22,7 @@
 
 LXC_MAPPED_UID=
 LXC_MAPPED_GID=
+SSH=
 
 # Make sure the usual locations are in PATH
 export PATH=$PATH:/usr/sbin:/usr/bin:/sbin:/bin
@@ -160,6 +161,116 @@ EOF
     return $res
 }
 
+install_dropbear()
+{
+    # copy dropbear binary
+    cp $(which dropbear) $rootfs/usr/sbin
+    if [ $? -ne 0 ]; then
+        echo "Failed to copy dropbear in the rootfs"
+        return 1
+    fi
+
+    # make symlinks to various ssh utilities
+    utils="\
+        $rootfs/usr/bin/dbclient \
+        $rootfs/usr/bin/scp \
+        $rootfs/usr/bin/ssh \
+        $rootfs/usr/sbin/dropbearkey \
+        $rootfs/usr/sbin/dropbearconvert \
+    "
+    echo $utils | xargs -n1 ln -s /usr/sbin/dropbear
+
+    # add necessary config files
+    mkdir $rootfs/etc/dropbear
+    dropbearkey -t rsa -f $rootfs/etc/dropbear/dropbear_rsa_host_key > /dev/null 2>&1
+    dropbearkey -t dss -f $rootfs/etc/dropbear/dropbear_dss_host_key > /dev/null 2>&1
+
+    echo "'dropbear' ssh utility installed"
+
+    return 0
+}
+
+install_openssh()
+{
+    # tools to be installed
+    server_utils="sshd"
+    client_utils="\
+        ssh \
+        scp \
+        sftp \
+        ssh-add \
+        ssh-agent \
+        ssh-keygen \
+        ssh-keyscan \
+        ssh-argv0 \
+        ssh-copy-id \
+        "
+
+    # new folders used by ssh
+    ssh_tree="\
+$rootfs/etc/ssh \
+$rootfs/var/empty/sshd \
+$rootfs/var/lib/empty/sshd \
+$rootfs/var/run/sshd \
+"
+
+    # create folder structure
+    mkdir -p $ssh_tree
+    if [ $? -ne 0 ]; then
+        return 1
+    fi
+
+    # copy binaries
+    for bin in $server_utils $client_utils; do
+        tool_path=`which $bin`
+        cp $tool_path $rootfs/$tool_path
+        if [ $? -ne 0 ]; then
+            echo "Unable to copy $tool_path in the rootfs"
+            return 1
+        fi
+    done
+
+    # add user and group
+    cat <<EOF >> $rootfs/etc/passwd
+sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
+EOF
+
+    cat <<EOF >> $rootfs/etc/group
+sshd:x:74:
+EOF
+
+    # generate container keys
+    ssh-keygen -t rsa -N "" -f $rootfs/etc/ssh/ssh_host_rsa_key >/dev/null 2>&1
+    ssh-keygen -t dsa -N "" -f $rootfs/etc/ssh/ssh_host_dsa_key >/dev/null 2>&1
+
+    # by default setup root password with no password
+    cat <<EOF > $rootfs/etc/ssh/sshd_config
+Port 22
+Protocol 2
+HostKey /etc/ssh/ssh_host_rsa_key
+HostKey /etc/ssh/ssh_host_dsa_key
+UsePrivilegeSeparation yes
+KeyRegenerationInterval 3600
+ServerKeyBits 768
+SyslogFacility AUTH
+LogLevel INFO
+LoginGraceTime 120
+PermitRootLogin yes
+StrictModes yes
+RSAAuthentication yes
+PubkeyAuthentication yes
+IgnoreRhosts yes
+RhostsRSAAuthentication no
+HostbasedAuthentication no
+PermitEmptyPasswords yes
+ChallengeResponseAuthentication no
+EOF
+
+    echo "'OpenSSH' utility installed"
+
+    return 0
+}
+
 configure_busybox()
 {
     rootfs=$1
@@ -230,34 +341,6 @@ EOF
     lxc-unshare -s MOUNT -- /bin/sh < $CHPASSWD_FILE
     rm $CHPASSWD_FILE
 
-    # add ssh functionality if dropbear package available on host
-    which dropbear >/dev/null 2>&1
-    if [ $? -eq 0 ]; then
-        # copy dropbear binary
-        cp $(which dropbear) $rootfs/usr/sbin
-        if [ $? -ne 0 ]; then
-            echo "Failed to copy dropbear in the rootfs"
-            return 1
-        fi
-
-        # make symlinks to various ssh utilities
-        utils="\
-            $rootfs/usr/bin/dbclient \
-            $rootfs/usr/bin/scp \
-            $rootfs/usr/bin/ssh \
-            $rootfs/usr/sbin/dropbearkey \
-            $rootfs/usr/sbin/dropbearconvert \
-        "
-        echo $utils | xargs -n1 ln -s /usr/sbin/dropbear
-
-        # add necessary config files
-        mkdir $rootfs/etc/dropbear
-        dropbearkey -t rsa -f $rootfs/etc/dropbear/dropbear_rsa_host_key > /dev/null 2>&1
-        dropbearkey -t dss -f $rootfs/etc/dropbear/dropbear_dss_host_key > /dev/null 2>&1
-
-        echo "'dropbear' ssh utility installed"
-    fi
-
     return 0
 }
 
@@ -315,12 +398,12 @@ remap_userns()
 usage()
 {
     cat <<EOF
-$1 -h|--help -p|--path=<path>
+$1 -h|--help -p|--path=<path> -s|--ssh={dropbear,openssh}
 EOF
     return 0
 }
 
-options=$(getopt -o hp:n: -l help,rootfs:,path:,name:,mapped-uid:,mapped-gid: -- "$@")
+options=$(getopt -o hp:n:s: -l help,rootfs:,path:,name:,mapped-uid:,mapped-gid:,ssh: -- "$@")
 if [ $? -ne 0 ]; then
     usage $(basename $0)
     exit 1
@@ -336,6 +419,7 @@ do
         -n|--name)      name=$2; shift 2;;
         --mapped-uid)   LXC_MAPPED_UID=$2; shift 2;;
         --mapped-gid)   LXC_MAPPED_GID=$2; shift 2;;
+        -s|--ssh)       SSH=$2; shift 2;;
         --)             shift 1; break ;;
         *)              break ;;
     esac
@@ -384,3 +468,28 @@ if [ $? -ne 0 ]; then
     echo "failed to remap files to user"
     exit 1
 fi
+
+if [ -n "$SSH" ]; then
+    case "$SSH" in
+        "dropbear")
+            install_dropbear
+            if [ $? -ne 0 ]; then
+                echo "Unable to install 'dropbear' ssh utility"
+                exit 1
+            fi ;;
+        "openssh")
+            install_openssh
+            if [ $? -ne 0 ]; then
+                echo "Unable to install 'OpenSSH' utility"
+                exit 1
+            fi ;;
+        *)
+            echo "$SSH: unrecognized ssh utility"
+            exit 1
+    esac
+else
+    which dropbear >/dev/null 2>&1
+    if [ $? -eq 0 ]; then
+        install_dropbear
+    fi
+fi